Magnetic resonance imaging is an image taking method by which a nuclear spin in an examined subject placed in a magnetostatic field is magnetically excited by a Radio Frequency (RF) pulse at a Larmor frequency thereof so as to generate an image from magnetic resonance signals (hereinafter, “MR signals” as necessary) generated due to the excitation.
Conventionally, a parallel imaging (PI) method is known as one of high-speed image taking methods. Generally speaking, when the PI method is implemented, an effort is made to shorten the time period required by the image taking process (hereinafter, “image taking period”), by acquiring k-space data while performing a down-sampling (thinning) process thereon. Because a folded image is generated from the k-space data acquired while performing the down-sampling process, an image that is not folded is obtained by, according to the PI method, performing, on pieces of k-space data acquired in correspondence with a plurality of channels at different sensitivities, a reconstructing process using a difference in sensitivity between the channels. However, when the thinned-out ratio (hereinafter, the “Parallel Imaging Factor (PIF)”, as necessary) is increased, the Signal-to-Noise Ratio (SNR) drops. Thus, there is a certain limit to high-speed image taking processes. Also, because the PIF has a limit, there is also a certain limit to improvements on time resolutions.